What it means
Communication with Door Window Motor B was not received as expected. The code does not specify the motor's bus interface or window features.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
Door window motor B is associated with a power window and communicates with other modules over the vehicle network. U0223 is set when the reporting module does not receive the expected messages from motor B; the code alone does not identify whether the motor, its supply, wiring, or network path is at fault.
Common causes
Most likely first.
- Module unpowered
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and record freeze-frame details, checking whether U0223 occurs with low voltage or other communication codes.
- Operate the window controlled by motor B from its available switches and note whether the fault is absent, intermittent, or limited to one control.
- Inspect motor B's connector and the door harness for corrosion, loose pins, water intrusion, or wires damaged by door movement.
- Check motor B's power and ground and test the relevant network wiring for opens or shorts using the vehicle wiring diagram.
- If those checks pass, test motor B's communication and operation according to the manufacturer's procedure.
Common fixes
- Restore battery charge if low voltage is found.
- Clean and secure motor B's connector if its contacts are poor.
- Repair damaged wiring or a failed power or ground connection to motor B.
- Repair a confirmed network fault on the motor B circuit.
- Replace motor B or its control component if testing confirms failure.
Can I keep driving?
The vehicle is generally drivable if the window is secure, but make sure it is closed or otherwise safely secured before setting off. A window that stops responding may remain open and compromise visibility, weather protection, or security.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.